Camera



Jan. 5, 1943.

F. T. SONNE 2,307,646

CAMERA Filed 001;. 26, 1940 4- Sheets-Sheet l [/Ziiiii:

F. T. SONNE CAMERA Filed Oct. 26, 1940 Jan. 5, 1943.

4' Sheets-Sheet 2 F. T. SONNE Jan. 5, 1943.

CAMERA 4 Sheets-Sheet 3 Filed Oct. 26, 1940 I l ii).

I i I I I I g I I I I I I I I I I I I I I I I I Jan. 5, 1943.

F. T. SONNE 2,397,545

CAMERA Filed 061:. 26, 1940 4 Sheets-Sheet 4 Hun .lll

95\ IIIAIII III'IIIIHIIIII Patented Jan. 5, 1943 CAMERA Frederick T. Sonne, Golf, 111., assignor to Chicago Aerial Survey Company, a corporation of Illinois Application October 26, 1940, Serial No. 363,015

3 Claims.

The camera of the present invention is designed primarily though not exclusively for aerial photography, it being adaptable both for military and commercial purposes in the making of maps over an extended area.

Among the more essential objects of my invention the following are illustrative:

The provision of mechanism for correcting heretofore unavoidable photographic mistakes and inaccuracies due to parallactic displacement of the actual position of an object being photographed while the object and the camera are in relative motion.

The provision of viewing mechanism for producing a continuous clear, sharp and distortionless true-plan, still image of the object being photographed.

The provision of object viewing and picture taking mechanisms in which there is such coaction between the two as will insure production of a continuous, clear, sharp and distortionless trueplan still picture.

The provision of an organization of object viewing and picture taking mechanisms which is compact and adapted to be conveniently controlled by the camera-man from a central or common position.

The provision of an organization of object viewing and picture taking mechanisms in which readings taken from the viewing mechanism may be depended upon to show a correct photographic relationship between film strip and the object during continuous exposure of said strip.

The provision of a camera wherein all parts thereof are mounted as a unitary structure upon a common support so as to be capable of selective operation conjointly at any instant and for such period of time as is required for the taking of a continuous still picture of ground terrain.

Further objects and details will appear from the description of the invention in conjunction with the accompanying drawings, wherein- Figure 1 is a perspective view of the rear or top side of the camera which in use will be projected downwardly toward an aperture in the floor of the plane;

Fig. 2 is a skeletonized view of the driving mechanism for advancing the sensitized film at a properly synchronized rate and concurrently feeding the indicator strip which affords the data for synchronizing the film speed with that of the projected image and correcting the angle of the camera to coincide with the line of flight:

Fig. 3 is a plan view of the camera, with the top removed to expose the interior thereof;

Fig. 4 is a sectional elevation taken on line 44 of Fig. 3;

Fig. 5 is a sectional elevation taken on line 5-5 of Fig. 3;

Fig. 6 is a detail taken on line 66 of Fig. 5 showing the indicator for registering the amount of film wound up on the receiving spool;

Fig. 7 is a wiring diagram for the motor which feeds the film and the indicator strip;

Fig. 8 is a top view showing the gimbals for mounting the camera to permit angular adjustment in any direction; and

Fig. 9 is a side elevation of the camera.

The camera is housed within a rectangular casing Ill, having side walls H and [2, a rear or top wall I3, and a lower or front wall l4. The interior of the casing is provided with spaced partition walls l5 and 16 which diverge laterally attheir forward ends I1 and 18 to afford a throated passage 19 for the light rays focused by a lens 20 which is mounted at the lower end of a tube 2| provided around its upper end with a flange 22 which is connected to the lower wall [4 of the casing.

The partition walls I5 and I6 merge into a cross partition wall 23 which divides the casing into two sections, the first of which provides a mounting for the mechanisms involved in the exposure of the film, and the second of which affords a mounting for the indicator strip and associated mechanisms- The spaced partitions l5 and I6, at their upper ends merge into laterally extending plates 24 which lie in the same plane and afford a table top for the mounting of a fixed plate 25 and an adjustable plate 26, the contiguous inner edges of which plates are beveled at 21 to afford, in conjunction, a narrow slit or gap for the passage of the light rays to the sensitized film F, which is held in close adjacency with the light slit by a rounded shoe plate 28. The adjustment of the plate 26 permits the width of the slit to be varied.

The film is fed from a delivery spool 29 located within the space defined by the flared partition wall l8 and passes over an idler roll 30, and thence in ,contact with the aligned surfaces of the plates 25 and 26 and a wedge plate 3|, and thence over a vacuum feed roll 32 to the takeup spool 33 which is located within the space defined by the flaring partition wall H. The wedge plate is adjustable by a screw 3| having a cali brated knob 31* which enables the operator to accurately vary the width of the exposure slit.

With the lens 20 in focus with the ground image, a minute fraction of the image will at film, so that during each instant oi! exposure the film and the ground image will be relatively stationary to one another, which results in a progressive exposure of the film and the imprint of a sharply defined continuous image.

The vacuum feed roll 82 is provided in its surface with a multiplicity of apertures 38 which, when the roll is attached to a suitable suction device, will create a vacuum which serves to hold the film firmly against the roller surface so that no slippage can occur, and an even and uniform ieeding or the film will be insured.

The film passes under a guide roll 35 which holds it in close adjacency to the surface oi the feed roll, and an interior shoe 8% is provided which blocks of! the vacuum on the delivery side or the feed roll, so that the film, after passing over a guide roll 37, will be freed from the pull of the vacuum and pass forwardly to the takeup roll 33. The feeding mechanism for the rolls and other associated mechanisms will be presently described in detail.

In order that the operator may have before him a constant image of the area presented to the sensitized film, I provide an elongated indicator strip 38 (Fig. 2) (endless or otherwise),

having a run which passes between a clear glass plate 39 and a ground glass plate it having marked thereon a longitudinal line or lines 82 visible through an elongated window 4i in the rear or top of the camera casing. However, the longitudinal line might be inscribed on the indicator strip itself without modifying the nature of the visual indication presented to the eye of the operator.

The indicator strip is itself transparent and is provided with a plurality of uniformly spaced cross lines 53, or other suitable indicia which travel with the strip, and where anendless strip is employed it is fed around a power driven sprocket roll it which is axially aligned with the vacuum reed roll 32 and around an idler roll 45 which is axially aligned with the idler roll 30. It is not essential, howeventhat the strip be endless, since like results would attend the use of a strip fed from spool to spool in synchronous relation to the advance of the film, so that a light my passing through a lens in a lens tube 46 will be focused upon the ground glass window plate 40, and will be subtended by the visible lines on the upper turn of the indicator strip and on the ground glass.

The result of this arrangement is that a traveling image of the ground area currently exposed through the camera slot will be presented to the eye of the operator, and so long as a given landmark on the ground maintains coincidence with a given calibrated spot on the indicator strip, the cameraman will know that the ground image is being accurately exposed and photographed on the moving sensitized film. If, however, a given landmark appears to move to the right or the left of the longitudinal line or advances or retreats with respect to the cross lines or equiva lent markings on the indicator strip, the cameraman is informed of the fact that an adjustment of the camera is required to bring the given landmark back to its original position on the moving indicator strip.

Thus, if the plane turns to the right or the left, the index image will swerve inversely either to the left or right of its original position on the line, and likewise, if the feeding speed of the sensitized film is out oi synchro with the speed of advance of the ground image as presented to the camera, or ii! the plane tilts up or down, the image as seen on the indicator will appear to advance or retreat from its original position, which gives the information required in readjusting the feeding speed of the film.

For convenient reference it is usually desirable for the observer to center his eye upon some ground object, as for instance a road or railroad track which aligns with the longitudinal line or lines on the ground glass, and by proper angular adjustment of the camera to prevent the shifting of said landmark away from the longitudinal position by suitable adjustments from time to time to compensate for erratic movements of the aeroplane.

If for instance in military observations it is desirable to photograph a railroad track in enemy territory the plane pilot will endeavor to maintain a course immediately above the railroad track and at the elevation required, while the photographer keeps the image of the railroad in the center position by proper angular adjustments of the camera and compensates for the variations of ground speed by the necessary regulation of the feeding speed of the film. The

provided with a spiral gear El meshing with a spiral gear 52 on a primary transmission shaft 53 provided at its opposite end with a spiral gear-6t meshing with a spiral gear 55- on a secondary transmission shaft 55 which is provided with a spiral gear 51 meshing with a spiral gear 58 surrounding and rigidly secured to a sleeve 59 having on its inner end a clutch head E6. The sleeve may be moved in and out by means of a rod 6| carrying a button 82 within convenient reach. of the operator. The driving head 50 is adapted to engage with a driven clutch head 63 which is carried by the shaft which mounts the vacuum feed roller 32 which draws forward the sensitized film F.

The arrangement is one which permits the indicator strip to be driven independently of the sensitized film when the clutch members are released, in order to enable the operator to take suitable observations of the ground area traversed, without beginning to take the continuous photograph until the area to be photographically mapped comes within proper range of the indicator strip, after which, by throwing the clutch, the indicator strip and sensitized him will move in unison, so that the operator will at all times have a visual record of the film section currently traversing the exposure gap.

The endless indicator strip also passes over the idler roller t5 mounted on the end of the shaft for the roller 38, around which the film.

building up of the diameter of the exposed film on the takeup spool.

In order to maintain a continuing record of the amount of film exposed, a lever arm 56 is with a pinion ID on a shaft H extending outwardly through the top wall of the casing and provided with a disk I2 having a pointer 13 which coacts with a ring of indicator marks I4 on a dial 15, so that as the diameter of the film roll increases the pointer 13 will gradually turn to indicate the amount of film which has been exposed.

The variable speed motor is of any suitable standard form which may be wired in conformity with the diagram shown in Fig. 'I, or in any other suitable manner, and which is adjustable as to speedby the turning of a button 16 within convenient, reach of the operator, so that by suitable adjustments the feeding speed of the sensitized film and the indicator strip can be controlled.

The camera as a whole is mounted upon a lrame comprising standards 11 which rest directly upon the base 18 of the aeroplane fuselage in proper position to bring the lenses of the camera directly above an aperture '18 through which an unobstructed view of the ground is obtained. The standards are connected at their upper ends by angle bars 80 provided with inwardly projecting lugs 8i which provide mountings for a suspended base ring 82 which is hung from bracket arms 83 mounted between upper and lower cushion disks '4 held in place by suitable through bolts 85 and cap washers 86, which bolts are entered through the lugs Bi so that a firm base support is afforded for the camera, which,

however, is cushioned against vibrations by the disks 8|, which are made of rubber or the like.

The base ring 82 surrounds the lower portion of-the camera and affords a direct mounting for a rotatable adjustable ring 81. which is provided with diametrically spaced arms 88 and "provided with trunnion points 9! which provide a gimbal mounting for a tilting frame Si, which surrounds the medial portion of the camera and is provided on each side in a fore and aft direction with a boss 82 provided with a pivoted clamping head 93 which, in conjunction with the boss, affords a journal mounting for a trunnion 94 outwardly projecting from the'adjace'nt wall of the camera casing, v I

The rotatable adjustable ring." is provided with a series or calibrations l! which register with a pointer 98 on the base'ring 82, so that the operator can turn the ring 81, with the parts supported thereby, to set the camera in angular relation to the longitudinal axis, or the plane which is represented by the pointer 06.

relation to the speed of the plane, taking due account of the altitude and the speed at which the visible image of the landscape will move across the exposure aperture oiqthe camera. such preliminary adjustments it is also use w to take due account or the lateral driit or the plane due to any wind blowing crosswise to the course of the aeroplane and to rotate the camera to thedegree necessary to maintain the lore and actual line of flight rather than the axis of the plane.

In making these adjustments, the photographer will observe the progressively exposed topographical image on the ground glass, which will be constantly traversed by the calibrated indicator strip, and by observing conspicuous marks on the landscape and by more precisely adjusting the speed of the motor it will be possible to bring the feeding speed into synchronism with the speed of the plane before the ground area to be photographed is reached.

At the proper time the photographer will depress the clutch button which imparts the desired feeding speed to the sensitized film, which will begin to move across the exposure gap at a rate coincident with the movement of the visible image, so that the film by minute increments will be exposed to the landscape below, each increment being relatively stationary to the visible image during the instant of exposure, so that a sharp cut and continuous image will be imprinted upon the tllm. As the exposure continues, thephotographer will constantly observe the traveling image on the ground glass, and so long as the image maintains a fixed relationship with the calibrated indicator strip a correct exposure will be maintained on the sensitized film.

If, however, a given point in the observed image moves to the right or left or the center line on the ground glass, it will indicate that the plane has rolled to the right or lert on its longitudinal axis, orturned right or left on its horizontal axis, and aflord the n indication for the photographer to correct against such erratic movements by adjusting the camera to the left or right, as the case may be, until the index landmark regains its proper position.

If, on the other hand, the index landmark advances or retreats with respect to the markings on the indicator strip, the photographer will adjust against changes or speed or tilting of the plane until the image is again in proper register on the indicator strip.

. By reason or the multiple adjustments afforded by the mounting for the camera and the variable speed 01 the motor, it is possible for the photographer to maintain a very accurate record image or the area traversed by the plane, with due and instant corrections for aberrations in the pointing or the camera resulting from the unavoidable erratic motions to which the plane is subjected. Thus, in following a straight railroad line, for instance, if no correction were made for the lateral rolling movements of the plane, the image recorded upon the sensitized film would present the appearance of a sinuous rather than a straight stretch of track, and in like manner, it correction were not made for the up and down tilting movements of the plane, the image would be erratically Ioreshortened so that its value as a topographic record would be seriously impaired.

The method of mounting the camera and the adjustments provided for enable instant compensation to be made against such inaccuracies, so that a true record of the ground area below the line of flight will be secured, which is oi. primary importance, particularly in military operations. I

Although the apparatus has been described with particularity as to detail, it is not the intenart axis of the camera in coincidence with the 73 shown, since variations can be made therein .have been designed particularly for downward exposure from an aeroplane, it is not the intention that the use of the camera be thus limited, since it can be advantageously employed for lateral exposure from a moving ground vehicle or from a boat, ship, or the like.

Furthermore, although it is preferred to employ a constantly open exposure slit of the character described, the indicating features of the present invention can be successfully employed with a shutter camera having a shutter movement properly synchronized with the advance of the film, so that it will be understood that in the claims, unless otherwise limited, it is the intention to broadly cover an indicator strip of the general character described, and that its use is not confined to the particular kind of camera here shown.

I claim:

1. A camera for producing a continuous, trueindicative of a correct photographic relation of the camera to said terrain and including a plan, still photograph of ground terrain from an airplane in flight, said camera comprising a vertically disposed, manually tiltable casing rotatable about a vertical axisand having mechanism for visually imaging said terrain and disclosing any deviation of the visual image from a position indicative of a correct photographic relation of the camera to said terrain and including a screen at the top of the casing upon which said image is adapted to be projected, a continuously moving member in said casing and having a stretch disposed parallel to and visible through said screen,

said member having spaced apart transverse lines disposed parallel to and visible through said screen and said screen having associated therewith longitudinal lines in coaction with said transverse lines to'indicate by the position of said image said correct photographic relation of the camera to said terrain, said longitudinal lines also disposed parallel to the fore and aft axis of said camera, means upon the casing for controlling the speed of said continuously moving member to neutralize the visual image movement of said terrain, and mechanism upon the casing for imaging the terrain upon a continuously moving film strip contained in the casing and for applying the neutralized correction to said strip.

2. A camera for producing a continuous, trueplan, still photograph of ground terrain from an airplane in flight, said camera comprising a vertically disposed manually tiltable and horizontally rotatable casing having mechanism for visually imaging said terrain and disclosing any I deviation of the visual image from a position screen at the top of the casing upon which said image is adapted to be projected, a continuously moving member having a stretch disposed parallel to said screen, said member having spaced apart transverse lines disposed parallel to and visible through said screen and said screen having associated therewith longitudinal lines in coaction with said transverse lines to indicate by the position of said image said correct photographic relation of the camera to said terrain, said longitudinal lines also disposed parallel to the fore and aft axis of said camera, means upon the casing for controlling the speed of said continuously moving member to neutralize the visual image movement of said terrain, and mechanism carried by the casing for imaging the terrain upon a continuously moving film strip contained in the casing and for applying the neutralized correction to said strip, said film strip moving in a plane parallel to the direction of motion of said continuously moving member.

3. A camera designed to be mounted on an airplane in flight for taking a continuous picture of the ground terrain, said camera having a sight aperture at its top and an indicating line parallel with the indicated line of flight visible at said aperture, and having a downwardly directed exposure aperture, means for supporting a photographic film so as to dispose a portion thereof forcontinuous travel parallel with the terrain across the exposure aperture, means including a driven indicating element for visually imaging the terrain over which the plane is flying, Said element having a portion arranged to travel parallel with said portion of the film in line with the sight aperture and provided with transverse indicating lines, means for imaging on.the film the terrain over which the plane is flying, means for driving the driven element at a speed proportionate to the speed of the plane for producing a terrain image visible at the sight aperture, a clutch device whereby the film supporting means may be coupled to the driving means and operated to move the film in synchronism with the driven element and so as to give the film and the image thereon simultaneous movement at the point of incidence, and means for moving the film, the visual image producing means and the photographic image producing means in unison to different angles relative to the plane to maintain the film parallel with the terrain and the axes of the image producing means in line with the selected course when the plane deviates from a normal flying position relative to the terrain.

FREDERICK T. SONNE. 

